THE SILENCING OF SORTILIN AFFECTS THE CATHEPSIN D PROCESSING AND EXPRESSION IN EPIDIDYMAL CELLS

ANTONIO ALBERDI; CARVELLI L; SOSA MIGUEL ANGEL; LEIVA N; AGUILERA AC

San Luis

Congreso; XXXV Reunión Anual de la Sociedad de Biología de Cuyo; 2019

Sociedad de Biología de Cuyo

Epididymal cells exhibit a significant secretory activity that contribute to sperm maturation. Some of these enzymes are highly secreted by the epithelium into the epididymal lumen, and it is thought that they participate in remodeling the sperm surface during sperm maturation.Lysosomal enzymes are found in the epididymal fluid due to an active secretion by the epithelium The intracellular transport of these enzymes is mostly regulated by M6P receptors (MPRS) in most eukaryotic cells, and significant levels of these MPRS were also found in rat epididymis. However, other receptors like sortilin have been implicated in the transport to lysosomes too. Cathepsin D (CatD) is transported and secreted into the lumen along with prosaposin (Psap). Based on cell models that involve other proteins in the transport and secretion of CatD, we intended to study the incidence of the membrane protein sortilin on transport and processing of CatD in epididymal cells. We performed an experimental model based on a cell line from rat epididymis (RCE-1), which was depleted of sortilin after transfection with sortilin pSilencer. By western blot, we observed that this silencing increase the expression other proteins, such as cation-dependent MPR (CD-MPR) and Psap. CatD is decreased under these conditions, but a different processing is observed given that an increase of the inmature form proCathepsin D (PCD) was observed. Meanwhile, a similar distribution was observed by IFI. These preliminary results suggest that PCD could be transported by sortilin and CD-MPR alternatively, but its processing is affected by the silincig of sortilin.